Machine tool



R. A. MAI-ILMElsTER MACHINE TOOL `Filed June 29, 1955 Jan. 21, 1,958

MACHINE TOOL Raymond A. Mahlmeister, Dayton, Ohio, assignor, by mesne assignments, to The Sheield Corporation, a corporation of Delaware Application June 29, 1955, Serial No. 518,877

4 Claims. (Cl. 51-89) This invention relates to grinding machines and more particularly to an apparatus for dressing grinding wheels.

It is an object of this invention to provide a dressing mechanism for association with a continuous article conveyor of a grinding machine to move into the grinding Zone between grinding operations and dress the grinding wheel to a predetermined contour and depth, thus maintaining grinding accuracy without interrupting conveyor movement and without any substantial delay in the grinding cycle.

It is a further object to provide such a mechanism wherein after a predetermined amount of grinding a grinding wheel is automatically moved inward into the path -of movement of a dressing means carried by an article conveyor whereby grinding accuracy is maintained and overgrinding of conveyed articles is prevented.

It is a further object to provide such a mechanism wherein diamond dressing elements are carried at each side of a conveyor wheel or the like into position for dressing engagement with grinding wheels adjusted inward at each side of the conveyor after a predetermined number of grinding operations to dress the wheels as the dressing elements are carried through the opposed grinding Zone.

Other objects and advantages of the invention will be apparent from the following description, the appended claims, and the accompanying drawing, in which:

Figure 1 is a view in elevation of a grinding machine for the continuous grinding of oil grooves across the end faces of automotive transmission pinions, the machine including the features of the dressing mechanism provided by the present invention,

Figure 2 is a plan view of the righthand portion of Figure 1 and illustrates the association of the grinding wheels with the article conveyor,

Figures 3 and 4 illustrate the grinding wheels in grinding association with a part moving between the grinding zones,

Figures 5 and 6 illustrate the mounting means for the diamond dressers and the association of the dressers with the opposed grinding wheels,

Figure 7 is diagrammatic illustration of the air actuated circuit for moving the grinding wheels inward,

Figure 8 discloses the electrical circuit for controlling the inward grinding wheel movement, and

Figure 9 illustrates diagrammatically the association of the control switches with the conveying wheel and the diamond dresser.

1 The present invention is directed to an improved apparatus for dressing grinding wheels and is particularly adapted for inclusion in grinding machines comprising a continuous article conveyor moving articles between stationary grinding zones. For purposes of disclosing this invention a particular grinding machine has been illustrated which includes a rotatable wheel or carrier which receives and carries pinions in pockets provided along its perpihery and moves the pinions between opposed grinding wheels which grind oil grooves on each of i Patented Jan. `21,

ice

the end faces of the pinions as the pinions move through the grinding zones. The present invention is adapted for inclusion in other materially different machines and for dressing application in materially dilferent grinding processes.

In the particular apparatus illustrated a continuous conveyor formed as a wheel or carrier 10 is rotatably mounted on a base 11 and driven by means of an electric motor 12 also supported from the base. The carrier 10 includes projecting fingers 14 along its periphery and provides pinion receiving pockets for carrying spaced articles supplied to the machine through loading means or chute 15. Carrier 10 rotates clockwise as viewed in Figure 1 and carries the pinions around and down through opposed grinding zones t-o be later described in detail and, following grinding, the pinions drop from the wheel 10 into a receiving chute 16 to be conveyed to the next operation.

Opposed grinding wheels 17 and 18 provide grinding zones at each side of the periphery of conveyor wheel' 10. The grinding wheels 17 and 18 are rotatable about parallel axes which are substantially perpendicular to the axis of carrier 10. Wheel 17 and its driving motor 20 are mounted on a support 21 which is movable toward and from the periphery of wheel 10 by a lead screw mechanism not shown in detail. Wheel 18 is similarly mounted on a support 22 and is driven by an electric motor 24. As the pinions are carried downward toward the grinding zones they engage a continuous belt 25 mounted on three freely rotatable pulleys 25, 27 and 28. Belt 25 maintains the pinions in the carrying pockets of carrier 10 during their traverse through the grinding zone. ln Figure 4 it will be seen that as a pini-on moves downward between grinding wheels 17 and 18 oil grooves 30 and 31 are simultaneously ground on the end faces of the pinion.

Due to the high rate of production possible with such a grinding apparatus, it is extremely important that time delays because of dressing be minimized. The present invention provides a dressing apparatus for use in such a machine which allows the continued operation of the machine without an interruption for dressing and which provides accurate control of the grinding wheel contour and the depth of grinding. ,i A

In the specific illustrated applicgion a holder 40 is mounted between a pair of the carrying fingers of carrier 10 and this holder mounts opposed diamond dressing elements 41 and 4t2 contoured to dress the opposed grinding wheels 17 and 18 to the desired configurations as the diamonds are carried downward through the grinding zone during the continued movement of the conveyor.

Structure is provided forA simultaneously moving the grinding, wheels 17 and 18 inward toward one another and toward the adjacent periphery of the carrier 10 fol-1 lowing the grinding of a predetermined number of pinions and only after the pinion immediately preceding the dia mond dresser holder 40 has cleared the grinding zones. Thus wheels 17 and 18 are automatically moved into dressing engagement with shaped diamonds 41 and 42 and are dressed as the diamonds move downward due to the continued rotation of carrier 10. It will be appreciated that because -of this, the maximum inward extent and the form of the grinding wheels is determined in each in stance by the proles of diamonds 41 and 52. This prevents excessive grinding -of the articles.

Supports 21 and 22 are movable toward and from one another through a conventional lead screw-lead nut structure which has notl been illustrated in detail. Each of the lead screws are threaded within a nut fixed to the associated support and the lead screw itself is prevented from axial movement. -Thus upon rotation of the lead screw the nut is moved, carrying the support with it.'4 In aseoso Fig, 7 it. will be seen that the, lead. screw 50 for support 21 is driven through a ratchet wheel 51 rotated upon movement of a pawl S2. Lead screw 54 for support 22 is similarly rotated to move its associated support upon actuation of wheel 55 by pawl 56. Each of the pawls 52 and 56 are adapted for movement to rotate wheel El and 55 upon extension of pistons 57 and 5S within cylinders 59 and 6i). Air is supplied under pressure from a suitable source through conduit 6ft and is metered through solenoid control valves 62 and 6.3 upon energization of solenoid 64 and 65 to extend the pistons, retract the pawls 52 and Se, and rotate lead screws 5d and 54 to move the wheels inward the desired amount for dressing.

This inward dressing movement of the grinding wheels is accomplished automatically, after a predetermined number of articles have been ground and after the article preceding diamond holder 4i) has passed through the grinding zones, by means of the electrical system of Figures 8 and 9.

Switch 70 mounted on a fixed portion of base ll has its contacting roller positioned to engage the pinions as they carried around by conveyor carrier id. Switch 7d serves to energize a timer 71 each time an article passes the switch roller. Timer 7l is of a commercially available type and can be adjusted to actuate a relay and close a switch la after a predetermined number of articles have been ground to condition the circuit for dressing. Switch 72 is also mounted in a fixed position and its roller is positioned to engage a cam 73 which rotates with wheel 10. It will be noted that cam 73 is disposed relative to diamond dresser lock dil. to actuate switch 72 after the article immediately preceding the dresser block has been ground. The closing of switch "il whe i tie circuit is properly conditioned energizes reiay C74 to close switch 74a and energize solenoids 6a, (i5 to move the grinding wheels inward into position for dressing engagement by the diamond. Timer '7i is also reset. Switch '75 is provided for manual control of the dressing cycle. This is one exemplary form which the circuit may take and other circuit arrangements can be utilized.

Thus it is seen that a dressing mechanism has been provided which has material advantages in grinding machines utilizing continuous conveyor devices. Through application of the teachings of this invention continuous grinding is made po ible with only a momentary loss of time for dressing wln e the conveyor continues its movement. Through lthe adjustments provided the dressing can be automatically carried out after a predetermined amount of grinding has been performed. Grinding wheel accuracy is maintained and the grinding of parts to depths beyond that desired is impossible.

While the form of apparatus Lierein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this preci e form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

l. A grinding apparatus comprising a base, feeding means including a wheel rotatably mounted on said base series of spaced article receivers along its pee a grinding wheel, l"

drive means connected to the g Ywheel, means carrying said grinding wheel and ive means from said base with the grinding wheel periphery disposed adjacent one side of said wheel for Anent with the articles as they pass through t ling zone at the grinding wheel periphery, the f unt of material removed being determined by the csition of the grinding wheel relative to the feeding '.ns, dressi g means carried hy said feeding means for .1 vement ti rough t te grinding zone, said dressing means ha a dressing profile corresponding to that to be ground into the article. and extending from the. feeding means for engagement with the grinding Wheel periphery during continued rotation of the feeding wheel and means in the carrying means for the grinding wheel for moving the grinding wheel inward toward the feeding wheel a predetermined amount following the grinding of the article immediately preceding the dressing means and into position for engagement with the said dressing means, whereby the grinding wheel form is maintained and the possibility of excessive grinding is eliminated.

2. A grinding apparatus comprising a base, a grinding wheel, drive means for the grinding wheel, article feeding means comprising a continuous system of article receivers, means mounting said grinding wheel and its drive means from said base adjacent said feeding means, loading means on said base for loading articles on said feeding means for grinding and receiving means for receiving articles after they are carried through a grinding zone at the periphery of the grinding wheel, the amount of material removed in grinding being determined by the proximity of the grinding wheel periphery to the feeding means, dressing means carried by said feeding means, adjustment means in said apparatus for moving said grinding Wheel toward said feeding means a predetermined amount, means in said apparatus associated with said feeding means for counting the articles as they are ground and for conditioning said adjustment means for actuation after a predetermined number of articles have passed through the grinding zone, and a second means responsive to the grinding of the article immediately preceding the dressing means for energizing said grinding wheel adjustment means when so conditioned for movement toward the feeding means a predetermined amount between grinding operations for engagement with said dressing means, whereby the grinding wheel form is maintained and the possibility of excessive grinding is eliminated.

3. A grinding apparatus comprising a base, feeding means including an article feeding wheel rotatably mounted on said base and having a series of spaced article receivers along its periphery carrying the articles so that their ends protrude from the Wheel, a pair of grinding Wheels, means mounting said grinding wheels from said base for rotation about spaced axes perpendicular t0 the wheel axis and adjacent the periphery of the wheel on opposite sides thereof, whereby a grinding Zone is provided at each side of the wheel for grinding the protruding ends of the articles, means for loading articles onto said receivers and means for receiving articles after grinding, dressing means carried by said wheel including diamond dressers extending to each side of the feeding wheel for engagement with the grinding wheels, means in said grinding wheel mount for adjusting the grinding wheels inward toward the adjacent sides of the feeding wheel, counting means associated with said feeding means for conditioning said adjustment means following the grinding of a predetermined number of articles, and means responsive to the grinding of the article immediately preceding the dressing means for energizing the adjustment means when so conditioned to move the grinding wheels inward for dressing engagement with the dressing means, during continued rotation of the feeding wheel whereby the grinding wheel form is maintained and the possibility of excessive grinding is eliminated.

4. A grinding apparatus comprising a base, a grinding wheel, drive means connected to said grinding wheel, means mounting said grinding Wheel and its drive means on said base, article feeding means supported from said base comprising a series of spaced article receivers for the continuous sequential feeding of articles to be ground through a grinding zone in association with the grinding wheel, they amount of material removed from each article during its movement through the grinding zone being determined by the proximity of the grinding wheel to the feeding means, dressing means carried by said feeding `means between a pair of article receivers for movement through the grinding zone and for dressing engagement with the grinding wheel at a point of maximum allowable grinding depth, power actuated adjusting means in said mounting means for moving the grinding wheel inward toward the article feeding means, counting means associated with said feeding means for conditioning said adjustment means following the grinding of a predetermined number of articles, and means responsive to the grinding of the article immediately preceding the dressing means for energizing the adjustment means when so conditioned to move the grinding wheel inward for dressing engagement with the dressing means during continued article feeding, whereby the grinding wheel form is maintained and the possibility of excessive grinding is eliminated.

References Cited in the le of this patent UNITED STATES PATENTS Landis Feb. 20, 1912 Theler Dec. 20, 1932 Bergfeldt Nov. 19, 1940 Hutchinson Sept. 20, 1949 Haas Dec. 23, 1952 Leslie June 9, 1953 FOREIGN PATENTS Great Britain Sept. 7, 1934 

